Articulatory rate and perceptual constancy in phonetic perception.

The perception of syllable-initial stop consonants as voiced (/b/, /d/, /g/) or voiceless (/p/, /t/, /k/) was shown to depend on the prevailing rate of articulation. Reducing the articulatory rate of a precursor phrase causes a greater proportion of test consonants to be identified as voiced. Subsequent experiments demonstrated that this effect depends almost entirely on variation in the duration of the syllable immediately preceding the test syllable; this, the duration of the intervening silent stop closure, and the duration of the test syllable itself all influenced the identification of the stop as voiced or voiceless. Variation in the tempo of a nonspeech melody produced no effect on the perception of embedded test syllables. Those manipulations which produce the major part of the influence of rate do so not by changing the context in which the stop is perceived, but rather by changing temporal concomitants of the constriction, occlusion, and release phases of the articulation of the stop itself. For this reason, an explanation for such effects based on extrinsic timing in perception is found to be wanting. Timing should, in the main, be regarded as intrinsic to the acoustical specifications of phonetic events, a view that is compatible with recent reformulations of the problem of timing control in speech production.